spi: clps711x: Remove duplicate code to set default bits_per_word and max speed

In the implementation of __spi_validate(), spi core will set transfer
bits_per_word and max speed as spi device default if it is not set for
this transfer. So we can remove the same logic in spi_clps711x_setup_xfer() and
spi_clps711x_transfer_one().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>